Tubular heater and method of making the same



May l, 1928.

J. C. WOODSON TUBULAR HEATER AND METHOD 0F MAKING THE SAME Filed sept. 2. 1926 Fl' j |NvENToR James C. h/ooczoofz wlTNEssEs; FEM b4 ATTORNEY Patented May .1, 1928. h

narranG sra'ras vParrain carica.

JAMES C. 'WOODSQN, OF MANSFIELD, OHIO, ASSIGNOR T0 WESTINGHOUSE ELECTRIC i 8a MANUFACTURING COMPANY, A CORPORATION 0F PENNSYLVANIL TTUBULAR HEATER Nn atmnonor MAKING THE SAME. i

` Application am september 2, 192s. serial No.' 133,137.

Y My invention relates to tubular heaters,

and particularly to flattened tubular heaters" A further object of my invention is to' provide means in a flattened tubular heater to prevent'short-circuiting of the heating coil. v

Other objects of my invention will be apparent from the disclosure.

` It has been found that in making a flat tened tubular heaterand particularly where the'heating coil is insulated by means of initially metallic, expansively oxidized material, there is danger of the two sides of a flattened coil coming into Contact with each -other andthereby causing a short-circuit.

By my invention I am able to aobviate this diiiiculty.l h

1n practicing my invention, according to the present embodiment, a heating lcoil has inserted within it an initially metallic eX- pansively oxidizable material and such Inaterial may also be placed on the outside. of the coil. These parts are' then placed'within a pipe that may be cylindrical and the oxidizable material oxidized by lsuitable means, such as steam under pressure. The method employed is more particularly disclosed and claimed in Reissue Pat. No. 16340 to C. B. Backer. The oxidized material,.expands to about 200% of itsori'ginal volume thereby filling-all of the available space. The pipe and lcoil are then flattened and the expansively oxidized'` material Within the coil will prevent short-circuiting be- -tween opposite sides of a flattened coil.

In the drawing, Fig: 1 is a longitudinal view, partially in section, of a. pipe with a heating coil therein before oxidation ofthe initially-metallic material; l y c Fig. 2 is a` transverse sectional view therethrough, taken on the line II--II of Fig. 1; Fig. 3 is a longitudinal view, partially in K magnesium oxide.

section, similar to Fig. 1, but .Completed tubulai' heater; and

Fig. 4. is a transverse sectional view taken on the line IV--IV of Fig. 3.

Referring to the drawing for a morecomplete description of the present embodiment of my invention, an electric heating coil 10 55 is placed in a coil 12 of initially metallic, expansively oxidizable material. A coil 14- composed of the same material as the coil 12, but of smaller diameter, is placed within the coil 10, as isshown in Figs. 1 and 2. The co assembled coils may then be placed in the pipe or tube 16 that'may be metallic.

After the coils 10, 12 and 14 are placed in the pipe 16, the entire assembly is placed in a suitable compartment, such as an autog5 clave, and subjected to the action of an oxidizing agent, such as steam under pressure. After having been treated for the proper length of time, the coils 12 and 14 will be oxidized and, as a result, the coil 10 will be 70 imbedded in refractory insulating material. If the .coils 12 and 14 are made of maonesium, the resulting oxidized material wlll be showing the The pipe 16 and the coil 10 are then flat- 75 tened by any suitable means, such as a rolling machine. After thus .being flattened, the tubular heater will'have the general appearance shown in Figs. 3 and 4. If the endsof the coil 10 are connected to a source of electrical" energy, the device `will operate as a heater.

By placing the coil 14 within the coil 10, opposite sides 18 and 20 of the flattened coil will be prevented from coming in contact with each other during the process of flat tening,since there will be .a layer of initially-metallic eXpansively-oxidized insulating L, material therebetween. Any danger of I short-circuiting will, therefore, b e obviated.

While the initial shape of the pipe 16 and the coils 10, 12 and 14 is shown as cylindrical, it is obvious that other shaped coils and pipes might be utilized. Y

While lI have shown and described for purposes of illustration a .particular form of my invetion, it may, of course, be embodied in other forms without .departing .from the spirit and scope thereof7 :1S-set forth in the appended claim.

I claim as my invention:

The method of making'a tubular heater that comprises placing coils of initially metallic expansively oxldizable material both and flattening the tube lund the material therein.

In testimony whereof, I have hereunto subi scribed-filly name this 18 day of Aug. 1926.

JAMES G. VVOODSON. 

